SUPPRESSIVE EFFECT OF INTERLEUKIN-4 ON THE DIFFERENTIATION OF M1 AND HL-60 MYELOID LEUKEMIC-CELLS

The effect of interleukin-4 (IL-4) on the proliferation and differentiation of myeloid leukemic cell lines was studied in vitro. A culture of murine myeloid cell line, M1, with lipopolysaccharide (LPS) from Escherichia coli, induced differentiation into macrophages that expressed Fc receptors and phagocytic activity. IL-4 did not induce the differentiation of M1 cells but inhibited the differentiation of M1 cells induced with LPS. On the other hand, LPS arrested the proliferation of Ml cells. IL-4 had no effect on the proliferation of M1 cells but restored the LPS-induced arrest of the proliferation of M1 cells. IL-1, IL-6 and tumor necrosis factor alpha (TNF-alpha) also induced the differentiation of M1 cells into macrophages and arrested proliferation. IL-4 suppressed the IL-1-, IL-6-, and TNF-induced differentiation of M1 cells and restored the arrested proliferation with IL-1, IL-6, and TNF. Similar results were obtained with human myeloid cell line HL60. These results suggest that IL-4 has a suppressive effect on the differentiation of myeloid cells into macrophages.